a b c d

b

For Lymen Series , $\nu_L = RZ^2 ( \frac{1}{1^2} - \frac{1}{\infty^2}) = Rz^2$ For P Fund series , $\nu' = RZ^2 ( \frac{1}{5^2} - \frac{1}{\infty^2}) = \frac{RZ^2}{25} = \frac{\nu_L}{25}$